1. Field of the Invention
The present invention relates to a light source apparatus for an electronic scope or a fiber scope.
2. Description of the Related Art
A high intensity lamp, such as a halogen lamp, a mercury vapor lamp or a metal halide lamp is used as a light source of a light source apparatus for an endoscope. If the light source goes off due to expiration of the service life thereof or trouble during examination or an operation using an endoscope, it is necessary to replace the light source or the light source apparatus with a new one. It is not desirable that the endoscope stays in a body cavity of a patient during the replacement.
To solve this problem, it has been proposed to provide a separate auxiliary light source in addition to a main light source of a high intensity lamp, wherein if the main light source goes off, the auxiliary light source is used to illuminate a body cavity of a patient, so that an insertion portion of an endoscope can be entirely removed from the body cavity under the illumination by the auxiliary light source. For example, see Japanese Patent Applications Laid-open Nos. 2000-210245, H10-108826, and 2002-72106.
As the auxiliary light source is provided for emergency use and is seldom used, it is preferable that the auxiliary light source be as small as possible and tend not to deteriorate due to aging. However, if the auxiliary light source is made of a high intensity LED, the amount of light emitted therefrom is smaller than that of the main light source and, hence, there is a possibility that the amount of light of the auxiliary light source which may be sufficient for a fiber scope is insufficient for use with an electronic scope and, consequently, an image captured by a picked-up image of the electronic scope is too dark.
It is an object of the present invention to eliminate the drawbacks of the prior art mentioned above by providing a light source apparatus for an endoscope in which an on/off state of an auxiliary light source can be controlled.